Strange one. After a d-u yesterday I was testing various things and discovered that kblocks(tetris) ran sluggishly. Top showed it using 90% cpu and xorg 50%. Starting from the command line showed complaints about .smb/smb.conf and .smb/smb.conf.append being missing. What has this got to do with Samba I thought? The d-u had updated smbclient and libsmbclient. Removing the former had no effect, removing the lib would take out most of kde. Creating the files removed the complaint but nothing was logged to them and nothing improved.
Kernel was also updated. Same result with 2.37. None of kde was updated but lots qt4.
I tried other games that use the arrow keys. They are OK.
Unfortunately I can't remember the last time I tried kblocks, maybe weeks ago. I wont miss it but the interaction with Samba intrigued me. There is no debugging info for kblocks itself.